Twisting machine



J. K. P. MACKIE,

TWISTING MACHINE Dec. 26, 1967 4 Sheets-Sheet 1 Filed Sept. 8, 1964LARGE END y JHM.

Inventor 7Q Wml fi 3rd? O MID POIN SMALL END Dec. 26, 1967 J; 13,359,715

TWISTING MACHINE Filed Sept. 8, 1964 4 Sheets-Sheet 2 EFG 5% (e) IInvenlor Dec. 26, 1967 J. K. P. MACKIE TWISTING MACHINE 4 Sheets-Sheet 5Filed Sept. 8, 1964 Dec. 26, 1967 l J. K. P. MACKIE 3,359,715

TWISTING MACHINE Filed Sept. 8, 1964 4 Sheets-Sheet 4 Home United StatesPatent 3,359,715 TWISTHNG MACHINE John K. P. Maclde, Belfast, NorthernIreland, assignor to James Mackie & Sons Limited, Belfast, NorthernIreland Filed ept. 8, 1964, Ser. No. 394,851 Claims priority,application Great Britain, Sept. 11, 1963, 35,885/63 7 Claims. (Cl.57-58.65)

This invention relates to machines for twisting textile yarn. Morespecifically it relates to machines of the so-called two-for-one type inwhich the yarn being twisted is ballooned by a flyer between let-off andtake-up packages around a carrier bracket which supports the takeuppackage when the machine is of the inflow type, and the let-01f packageor packages when the machine is of the out-flow type. The carrier isrotatably mounted on the flyer spindle and is maintained stationarywithin the balloon despite the rotation of the flyer. Suitable drivenyarn feeding means such, for example, as loaded rollers or haul pulleysare provided to drag the yarn through the balloon from the let-offpackage or packages and feed it at a constant rate to a traversingdevice which lays the yarn evenly on the take-up package.

When the let-off point of the driven yarn feeding means is locatedbetween the ends of the take-up package, the length of the direct pathbetween either end of the package and the let-off point will differ fromthe length of the direct path between the centre of the package and thelet-off point. Consequently the tension of the yarn being laid on thetake-up package by the traversing device varies during each completetraverse cycle leading to an increased risk of yarn breakage andundesirable twist variation. (This variation will be referred tohereafter as are variation.) This is particularly the case with anin-flow type machine where the take-up package and the let-off point ofthe yarn feeding means have to be mounted close to each other on thecarrier bracket so as to minimise the size of the balloon.

It has also been found that when the take-up package is a cross woundconical package driven at constant speed then further yarn tensionvariation can occur during winding due to the conical shape of thepackage, the speed of rotation of the surface of the package(controlling the rate of take-up of the yarn) being greater at thelarger end of the package than at the smaller end. If the package isdriven through a slip clutch device then the difference in take-up speedcan be compensated for by clutch slippage but there is inevitably a lagbetween the increase of tension and the decrease in speed of the packageand vice versa, due to momentum effect. This leads to yarn looping andtension variation. The problem is particularly acute when the package isprecision wound due to the high traverse speed and is furtheraccentuated if the machine is of the in-flow type.

In a two-for-one twisting machine for delivering yarn on to a crosswound conical package in accordance with the invention the length of theyarn path between the letoif point of the driven yarn feeding means andthe point of lay of the yarn on the package is varied during eachtraverse cycle of the package by compensating means including a cam, sodesigned that the path length variation introduced substantiallycompensates for the path length change occasioned by arc variation (ashereinbefore defined) and for at least some degree of variation in therate of yarn take-up occasioned by the conical shape of the take-uppackage. Thus yarn tension variation during take-up is substantiallyreduced leading to yarn having a more regular twist and to less yarnbreakage during winding.

The compensating device preferably includes a guide arm which engagesthe yarn between the let-off point and the laying point and which ismoved in accordance with the cam shape so as appropriately to cause theyarn path to approach more or less closely to the direct path betweenthe let-off point and the point of laying at any moment. Preferably theguide arm moves in a plane perpendicular to the longitudinal axis of thetake-up package.

The cam may be either a rotary cam or the cam surface may be arranged toextend longtudinally. In the latter case, which is preferred, it isconvenient to cause the cam follower, or a runner carried thereby, toengage in the groove of a traverse scroll which also controls thereciprocation of the traverser, the cam follower engaging the scroll ata position 90 out of cycle with the traverse follower, so that the camfollower is reciprocated in a horizontal plane as is the traversefollower but lags the traverse arm laying the yarn on the take-uppackage by a distance of half the length of the package. The cam memberis preferably mounted for pivotal movement in a vertical plane, so thatit moves up and down in accordance with the shape of its cam surfaceengaged by the reciprocating follower which moves in a fixed horizontalline. The movement of the cam is transmitted to the yarn between thelet-oif point of the yarn feeding means and the laying point of the yarnon take-up package through the guide arm which is carried by the cam andacts to increase or decrease the length of the yarn path.

If the machine is of the in-flow type i.e. the take-up package and yarnfeeding means being carried by the stationary carrier bracket within theballoon, then it is preferred that the take-up package axis beperpendicular to the flyer spindle axis and that the guide arm eye belocated mid-way between the ends of the take-up package. The yarnfeeding rollers or haul pulleys are preferably arranged so that the yarnpasses to them directly in line with the axis of the flyer spindle sothat the yarn path within the balloon is kept as short as possible withthe result that the yarn tension is kept as low as possible.

The invention will now be further described with reference to theaccompanying drawings in which:

FIGURE 1 is a diagram illustrating the variation in the length of theyarn path between the yarn feeding means of a twisting machine, and theends and centre of the take-up package;

FIGURE 2 is a graph illustrating the variation in yarn path length whichis produced by are variation and package conicity eifect during eachtraverse cycle;

FIGURE 3 is a diagram showing one form of rotary cam to compensate forthe variations in yarn path length illustrated in FIGURE 2;

FIGURE 4(a) shows diagrammatically the form. of longitudinal cam whichcorresponds to the rotary cam shown in FIGURE 3 and FIGS. 4(b), 4(a),4(d) and 4(2) show four positions of the cam, cam follower, and traverseeye during a complete traverse cycle;

FIGURE 5 shows somewhat diagrammatically and by way of example, oneembodiment for a two-for-one twisting machine of the in-flow type inaccordance with the invention; and

FIGURE 6 is a view in the direction of the arrow VI in FIGURE 5 withcertain parts removed for clarity.

Referring to FIGURE 1 a precision cross wound conical take-up packagegenerally indicated at 2 is being supplied with twisted yarn from adriven yarn feeding means in the form of a pair of haul pulleys 4, theyarn passing from the haul pulleys through an eye 6 to a traversingdevice (not shown) which operates to lay yarn on the surface of theconical take-up package which is driven at a constant speed. As willreadily be seen, the direct yarn path AB between the eye 6 and eitherend of the package is longer than the direct yarn path AC between theeye 6 and the centre or mid-point of the package. Thus the length of theyarn path is constantly varying during each traverse cycle resulting invariation in the tension of the yarn if the take-up package and the haulpulleys are driven at a constant speed. In fact the maximum variation inthe yarn path is represented by the distance CD which is the differencebetween the arc BB and an are having the nadius AC. This variation,which will hereafter be called arc variation and which leads to thevariation in tension of the yarn, can result in irregular twist and inan increased number of yarn breakages.

As will also be apparent from examination of FIG- URE 1 the surfacespeed of the large end 8 of the conical take-up package 2 is greaterthan the surface speed of the small and for a constant speed of rotationof the package. Thus the tension in the yarn when it is being laid onthe larger half of the package will the greater than that when the yarnis being laid on the smaller half of the package. This tension variationwhich is caused by the conical shape of the package, will hereafter bereferred to as conicity effect.

When the yarn is being laid at the mid-point C of the conical package atthe start of a traverse cycle it will be assumed that the path length isat its zero position as can be seen on the graph illustrated in FIGURE2. As the traverser moves towards the smaller end of the package thecompensation required for arc variation increases, in the negativedirection (i.e. the compensator should act to reduce the path lengthrelatively to the zero position) as the path AB is longer than the pathAC, to a maximum at the small end of the package. At the same time aconstant degree of compensation for the conicity effect has to besupplied but in this case the speed of take-up is progressivelydiminishing due to the smaller diameter of the package at the smallerand than at the mid-point so that the compensation required for conicityis positive as compared with the negative amount needed to compensatefor are variation. Referring to FIGURES 2 and 3 and assuming that thepackage before Winding commences, has a small end diameter of 2%", alarge end diameter of 3 /2, a length of 10 and that its mid-point C islocated at a distance of 8 /2" from the let-off point of the yarnfeeding means, the compensation needed for are variation is l% units (inthis case 1 unit=1") and the conicity compensation needed is /4 unit sothat the yarn path length has to be reduced by /2 unit between themid-point and the small end of the package.

When the yarn is being laid between the small end and the mid-point thearc variation diminishes from .a maximum at the small end of the packageto zero at the midpoint whereas compensation for the conicity effect hasstill got to be provided for at the same rate as during the traversebetween the mid-point and the small end. Thus the compensation requiredfor are variation is +1 4 and the compensation for conicity is againequivalent to as can be seen from examination of FIGURE 2. Hence thecompensator has to act to increase the yarn path length by an amountequivalent to 2 units during traverse from the small end to themid-point resulting in a figure of +1 /2 from the Zero position when atthe mid-point.

During traverse from the mid-point to the large end the arc variationagain increases from zero to a maximum of -1 t units. As yarn is nowbeing laid over the larger half of the package the compensation requiredfor the conicity effect can be expressed as units so that the totalcompensation required during this quarter cycle can be expressed as -2leading to .a movement of the compensator to give a path length changeof /2 units from the zero position, at the large end.

During the last quarter cycle of traverse from the large end to themidpoint of the package the arc variation diminishes from 1% units tozero so the compensation required can be expressed as +1% and again theconicity effect has to be compensated for by an amount of units leadingto a total compensation or change in path length of /z units from theposition at the end of the previous quarter cycle so that the pathlength again reaches its zero position or length.

The shape of the rotary cam needed to provide the variation in pathlength to compensate for the arc variation and conicity effect duringthe complete traverse cycle is shown in dash lines at 12 in FIGURE 3...During rotation of the earn a yarn guide arm 14 pivoted at one end at 16and having guide eye 18 at its outer end engages the cam surface througha cam follower roller 20, is moved so that its guide eye 18 acts toincrease and decrease the length of the path of yarn passing through theeye, during each rotation of the cam. Thus as the yarn is laid from themid-point to the small end of the package the guide eye 18 is movedupwardly by an amount corresponding to /2 unit so as to shorten the yarnpath length by an amount equal to the increase in the yarn path lengthdue to are variation and conicity effect. During the next quarter cyclethe guide eye 18 would be moved downwardly to increase the length of theyarn path to compensate in the decrease in the path length resultingfrom the arc variation and conicity effect during the traverse from thesmall and to the mid-point. During the next quarter cycle the yarn pathlength would be decreased by movement of the eye 18 and increased againduring the last quarter cycle.

As can be seen from FIGURE 3 the rotary cam is symmetrical about thecentre line passing through the two points representing the mid-point ofthe package during the cycle. Thus the equivalent longitudinal cam whichis indicated at 22 in FIGS. 4(1)), 4(0), 4(d) and 4(e) should beactuated by cam follower which is or one quarter cycle, out of phasewith the point of lay of the yarn on to the package.

Assuming that the cam follower 24 is reciprocated in unison with thetraverse guide eye 26 (see FIGURE 4) then when the cam follower is atthe centre of the longitudinal cam 22 the traverse guide is laying yarnat the large end of the take-up package (FIGURE 4(a)). As the traverseguide moves back towards the mid-point of the package the cam followermoves to the right along the cam causing the cam to be forceddownwardly, or the follower to rise, this movement of the cam or camfollower being transmitted to a guide arm of the compensating device sothat the yarn path is relatively increased to compensate for thedecrease in the path caused by a combination of arc variation andconicity effect as explained herebefore. When the traverse guide movesfrom the mid-point to the small end (FIGURE 4(e)) the cam follower movesfrom the right hand end of the cam to the mid-point thereof allowing thecam to rise relatively to the follower or vice versa causing the guidearm of the compensating device relatively to decrease the path length.On movement of the traverse guide from the small end to the midpoint thecam follower moves from the mid-point to the left hand end of the cam tothe position shown in FIGURE 4(d) causing the maximum downward movementof the cam, or upward movement of the follower, to increase the pathlength by the maximum amount. On movement of the traverse guide from themid-point to the right hand or large end of the package the cam followermoves from the left hand end of the cam to the mid-point thereofallowing the cam to move upwardly by the maximum amount or the camfollower to move downwardly by the maximum amount to the position inwhich the path length variation introduced by the compensating devicereaches its smallest figure.

The cam illustrated in FIGURES 4(a)4(e) is shown in FIGURES 5 and 6embodided in a two-for-one twisting machine of the in-fiow type. In thismachine, yarn generally indicated at 28 is led from a number of supplypackages such as cops (not shown) through a tensioning device (also notshown) through a stationary guide eye 30, attached to the machine frameto the eye 32 of a rotating fiyer 34. From the flyer the yarn passesthrough an entrance passage 36 around a roller 38 to and up a passage 40extending co-axially with the flyer directly to the first groove 42 of apair of driven haul pulleys 44, constituting the yarn feeding means.

The yarn is laid on a conical take-up package 46 carried on a spindle 48extending at right angles to the flyer axis, by a traversing deviceincluding a rotated traverse scroll 50, and traverse arm 52. Thetraverse arm 52 is pivotally mounted at 56 to a block 58 slidablymounted in an opening in a bracket 60 carrying the traverse scroll, andhaving a follower 62 which engages in the groove in the scroll so thatthe traverse arm is reciprocated on rotation of the scroll.

The eye 54 of the traverse arm has a curved nose which engages againstthe side of the take-up package 46 and which is held thereagainst bymeans, not shown, biasing the arm 52 in the clockwise direction as shownin FIG- URE 5. As the diameter of the package 46 increases due to yarnbeing laid on it the eye 54, and hence the arm 52, can move outwardlyagainst the bias, which bias however still maintains the eye in closecontact with the surface of the package so that the yarn can be laid onthe package very precisely throughout the formation of the package.

The haul pulleys 44, package spindle 48, and the traversing device areall mounted on the common carrier bracket 60 which is rotatably mountedon the flyer spindle and which is maintained stationary despite therotation of the flyer by, for example, a magnetic holding device (notshown) such as that disclosed in our US. Letters Patent No. 3,264,813issued Aug. 9, 1966, or, if the flyer axis is horizontal, by the inertiaof its own weight.

Rotation of the flyer causes the length of yarn between the fiyer eye 32and the eye 30 or strictly speaking, the traversing device to billowinto a ballon and be whirled around the package 46 between inner andouter balloon guide rings 64, 66. The balloon is caused to take theshape shown in the drawings by a guide ring 68 located between the innerguide ring 64 and the eye 30;

For each revolution of the flyer two turns of twist are given to theyarn, one turn being inserted between the flyer eye 32 and thetensioning device (or eye 30) and the other between the eye 32 and thehaul pulleys 44.

The haul pulleys 44 are driven from the flyer spindle through a drivechain comprising .pulley 70 on the flyer spindle within the balloon andpulley 72 on a shaft 74 carried by the bracket, the two pulleys beingconnected by a non-slip belt 76. The traverse scroll is driven from theshaft 74 through a gear chain (not shown) carried on the bracket 60 andterminating in a skew gear 78. The spindle 48 of the package 46 is alsodriven from the gear chain by, for example, a chain drive (not shown)through a slipping clutch.

The machine incorporates a compensating device to allow for arevariation and conicity effect and which comprises the cam 22 describedwith reference to FIGS. 4(a), 4(b), 4(e), 4(d) and 4(e) and guide arm 80attached to the cam and being provided at its outer end with an eye 82through which the yarn passes in its path between the let-off point ofthe haul pulleys 44 and the eye 54 of the traverse. The longitudinal cam22 is pivotally mounted about a horizontal pivot 84, extending parallelto the spindle of the package 44, through two arms 86, a spring 87 beingprovided to bias the cam into contact with its follower. The roller 24forming the cam follower, is 1'0- tatably mounted on a shaft 88 carriedby a slide block 90 which engages in a slot in the bracket 60 and whichis provided with a follower or runner 92 engaging in the groove of thetraverse scroll 50, 90 out of phase with the traverse follower 62.

Thus on rotation of the scroll 50, not only is the traverse eye 54caused to traverse along the length of the package 46 but the camfollower 24 is reciprocated in a horizontal plane parallel to thetraverse follower. As the follower 24 is reciprocated the cam member 22is caused to pivot in a vertical plane about its pivot axis 84 causing acorresponding pivotal movement of the guide eye 82 of the compensatingdevice. As the eye 82 moves in a vertical plane the length of the directyarn path between the haul pulleys 44 and the eye 54 of the traversingarm 52 is varied as explained herebefore with reference to FIGURE 4, toprovide compensation for are variation and conicity effect during eachtraverse cycle.

In practice the cam shape will be such as to provide for substantiallyall of the. arc variation and the conicity effect produced by a typicalconical package (slight deviation from the theoretical cam shape may benecessary to achieve smoothness of motion of the follower). Conicalpackages having a somewhat different taper angle will be able to bewound on the machine which will, in this case, not provide completecompensation for the conicity effect. However a sufficient compensationfor this effect will be given to reduce the yarn tension variation to anacceptable level.

I claim:

1. A two-for-one yarn twisting machine comprising driven yarn feedingmeans, a traverse mechanism which lays the yarn in cross wind on aconical package, and compensating means to vary the length of the yarnpath between the let-off point of the driven yarn feeding means and thepoint where the yarn is laid on the package, said let-off point of thefeeding means being fixed and located in a plane perpendicular to thepackage axis approximately midway between the ends of the package, andthe traverse mechanism including a yarn guide movable longitudinally ofand parallel to the longitudinal axis of the package which arrangementwould normally produce arc variation, said compensating means includinga cam so designed that the path length variation introduced during eachtraverse cycle compensates substantially for the path length changeoccasioned by said arc variation and for at least some degree ofvariation in the rate of yarn take-up package, the compensating meansincluding a guide arm positioned to engage the yarn between the letoffpoint of the yarn feeding means and the laying point on the package andwhich is moved in accordance with the shape of the ca m so asappropriately to cause the yarn path to approach more or less closely tothe direct path between the let-off point and the laying point.

2. A yarn twisting machine as claimed in claim 1 in which the guide armmoves in a plane which is perpendicular to the longitudinal axis of thetake-up package.

3. A yarn twisting machine as claimed in claim 2 which is of the in-flowtype including a flyer having a spindle, the take-up package axis beingperpendicular to the axis of the flyer and the eye of the guide arm,being located substantially mid-way between the ends of the take-uppackage.

4. A yarn twisting machine as claimed in claim 3 in which the drivenyarn feeding means is so arranged that the yarn passes to it directly inline with the axis of the flyer spindle.

5. A two-for-one yarn twisting machine comprising driven yarn feedingmeans, a traverse mechanism which lays the yarn in cross wind on aconical package, and compensating means to vary the length of the yarnpath between the let-off point of the driven yarn feeding means and thepoint where the yarn is laid on the package, said let-off point of thefeeding :means being fixed and located in a plane perpendicular to thepackage axis approximately midway between the ends of the package, andthe traverse mechanism including a yarn guide movable longitudinally ofand parallel to the longitudinal axis of the package which arrangementwould normally produce arc variation, said compensating means includinga cam, a second yarn guide connected with the cam and engaging said yarnadjacent the let-off point of the driven yarn feeding means, and meansfor operating said cam for causing movement of said second guide wherebythe path length variation introduced during each traverse cyclecompensates substantially for the path length change occasioned by saidare variation and for at least some degree of variation in the rate ofyarn take-u occasioned by the conical shape of the take-up package.

6. A two-for-one yarn twisting machine comprising driven yarn feedingmeans, a traverse mechanism which lays the yarn in cross wind on aconical package, and compensating means to vary the length of the yarnpath between the let-ofi point of the driven yarn feeding means and thepoint where the yarn is laid on the package, said let-off point of thefeeding means being fixed and located in a plane perpendicular to thepackage axis approximately midway between the ends of the package, andthe traverse mechanism including a yarn guide movable longitudinally ofand parallel to the longitudinal axis of the package which arrangementwould normally produce arc variation, said compensating means includinga cam and movable means engaging the yarn and actuated by the camwhereby the path length variation introduced during each traverse cyclecompensates substantially for the path length change occasioned by saidarc variation and for at least some degree of variation in the rate ofyarn take-up occasioned by the conical shape of the take-up package,said cam having a longitudinal cam surface arranged so that it extendsin a direction parallel to that of the axis of the take-up package, saidcompensating means including a follower for said cam, said followerengaging in the groove of a rotatable traverse scroll controlling thereciprocation of traverse means acting to lay the yarn take-up packageso that it moves up and down in accord-,

ance with the shape of its cam surface on movement of the reciprocatingcam follower which movement takes place in the fixed line parallel tothe package axis, a guide anm carried by the cam, the movement of thecam being transmitted to the yarn through said guide arm. 1

References Cited 7 UNITED STATES PATENTS 1,858,205 5/1932 Ferier 5758.56 2,505,050 4/1950 Kimball 5758.65 X 2,773,344 12/1956 Van Hook 5758.65X 2,834,178 5/1958 Klein 5758.65 X 2,914,904 12/1959 Brown 5758.653,006,472 12/1962 Klein 5758.65 X 3,106,055 10/1963 Mackie 5758.7 X

STANLEY N. GILREATH, Primary Examiner.

1. A TWO-FOR-ONE YARN TWISTING MACHINE COMPRISING DRIVEN YARN FEEDINGMEANS, A TRAVERSE MECHANISM WHICH LAYS THE YARN IN CROSS WIND ON ACONICAL PACKAGE, AND COMPENSATING MEANS TO VARY THE LENGTH OF THE YARNPATH BETWEEN THE LET-OFF POINT OF THE DRIVEN YARN FEEDING MEANS AND THEPOINT WHERE THE YARN IS LAID ON THE PACKAGE, SAID LET-OFF POINT OF THEFEEDING MEANS BEING FIXED AND LOCATED IN A PLANE PERPENDICULAR TO THEPACKAGE AXIS APPROXIMATELY MIDWAY BETWEEN THE ENDS OF THE PACKAGE, ANDTHE TRAVERSE MECHANISM INCLUDING A YARN GUIDE MOVABLE LONGITUDINALLY OFAND PARALLEL TO THE LONGITUDINAL AXIS OF THE PACKAGE WHICH ARRANGEMENTWOULD NORMALLY PRODUCE "ARC VARIATION" SAID COMPENSATING MEANS INCLUDINGA CAM SO DESIGNED THAT THE PATH LENGTH VARIATION INTRODUCED DURING EACHTRAVERSE CYCLE COMPENSATES SUBSTANTIALLY FOR THE PATH LENGTH CHANGEOCCASIONED BY SAID "ARC VARIATION" AND FOR AT LEAST SOME DEGREE OFVARIATION IN THE RATE OF YARN TAKE-UP PACKAGE, THE COMPENSATING MEANSINCLUDING A GUIDE ARM POSITIONED TO ENGAGE THE YARN BETWEEN THE LETOFFPOINT OF THE YARN FEEDING MEANS AND THE LAYING POINT ON THE PACKAGE ANDWHICH IS MOVED IN ACCORDANCE WITH THE SHAPE OF THE CAM SO ASAPPROPRIATELY TO CAUSE THE YARN PATH TO APPROACH MORE OR LESS CLOSELY TOTHE DIRECT PATH BETWEEN THE LET-OFF POINT AND THE LAYING POINT.